The present invention relates to an optical sensor, which is used in connection with the guidance of a missile toward a target.
Optical sensors used to detect targets are known which form a sharp image of the target scene lying within the field of view of an optical system onto a planar sensor, which is constructed of a plurality of detector elements configured in a matrix. In an evaluation circuit, those signals which are clearly attributable to a target are selected from the signals of the detector elements. Based on this evaluation, the missile is then guided toward the target.
A condition for such a guidance is the requirement for a coordinate reference system, into which the characteristic motions of the missile, that is roll, pitch, yaw and flight direction, as well as the target coordinates and target movements are projected.
Such a coordinate reference system can be preset, for example, by an inertial system, for instance, a gyroscopic system, inside the missile. Another possibility lies in calculating the characteristic motion of the missile with the help of a rigidly installed sensor consisting of several detector rows, arranged, for example, in a T-shape, on which only a part of the target scene is imaged, and of an image processing unit, and in projecting from the coordinate system fixed with respect to the missile into the coordinate reference system. See, e.g., DE-OS 34 46 009. The detector rows of the sensor do not lie in the focal plane of the sensor's optical system, so that a "smeared" image is formed of a point of the target scene lying at infinity, for which this image is evaluated with respect to the spatial and time derivatives of the individual image points.